This invention relates to safety doors and more particularly to doors that resist forced entry from outside such as for example by forcing a deadbolt that is holding the door to the doorway frame to release or forcing the hinges from the door or doorway frame.
It is known to utilize multiple spaced apart deadbolts that resist forcible entry. This prior art technique has several disadvantages, such as for example: (1) the deadbolts only protrude a short distance into the frame of the door and thus can be forced free; (2) it is time consuming and inconvenient to individually move the deadbolts into place; and (3) the hinges can be forced out of the frame or the center of the door can be broken into such as by an axe.
U.S. Pat. No. 5,911,763 discloses a central actuator that moves a plurality of deadbolts into place at spaced apart locations around the periphery of the door through individual linkages, thus reducing the inconvenience of moving individual deadbolts into place one at a time. However, the lock disclosed in this patent relies upon linkages near the deadbolts at the periphery of the door that activate the three individual deadbolts and the deadbolts have only a short length within the door. It has several disadvantages, such as: (1) there are no deadbolts on the hinge side of the door so there are only a few short screws holding this side of the door in place against an impact that may pull the screws holding the hinges free; and (2) each of the linkage mechanisms includes three pivot points from the central actuator and provides little support for the door itself. Thus, in the case of some doors, an axe may be used to break the door itself.
It is known to use bars mountable on the inside of the door and held at several locations so that they extend across the door. While these bars provide overall strength, it is time consuming to put them in place and remove them when locking or unlocking the door. Moreover, they are unsightly.